Signaling system for single-track railroads



w. v. GROSJEAN SIGNALING SYSTEM FOR SINGLE TRACK RAILROADS Filed Nov. 23, 1946 April 11, 1950 I 2 Sheets-Sheet 1 l'lll-ll. h n

HIS ATTORNEY W. V. G ROSJEAN SIGNALING SYSTEM FOR SINGLE TRACK RAILROADS April 11, 1950 2 Sheets-Sheet 2 IN NTOB Wilbur V HIS ATTORNEY Filed Nov. 25, 1946 N N N 52 NN N m H -J 5% 5m QM a A L A RWI H m m0 T I u N I l .m 7

sfih F 5% 5 L r LE \Q L r r m SN Mk MNN NE E %N MN .NN .No

Patented Apr. 11, 1950 SIGNALING SYSTEM FOR SINGLE IRAC K RAILROADS Wilbur V. Grosjean, Omaha, Nebr., assignor to The Union Switch and Signal Company, Swissvale, Pa a corporation'- of Pennsylvania Application November 23, 1946, Serial No. 711,851

11 Claims.

My invention relates to signaling systems for single track railroads, and more particularly to improvements in such systems to provide increased stopping distances required for the protection of high speed trains while avoiding unnecessary restrictions upon the movement of trains which are approaching a meeting point such as a passing siding, from opposite directions.

-The principal object of my invention is the provision of means by which the engineman of a train approaching a possible meeting point such as a passing siding, by performing some act of acknowledgment to indicate whether or not it is his intention to stop, such as byblowing a whistle or the like, maycontrol the aspects of the signals for the block in advance of his train, for both directions. More particularly, my invention provides means by which the engineman is enabled to cause the entering signal for the single track block beyond the siding which he is approaching to indicate stop or proceed, depending upon whether or not the siding is a designated meeting poinl' and thereby avoid the display of' a succession of restrictive signals to an opposing train, permitting it to approach a meeting point at a relatively higher speed thanv would be the case, for example, if the block signals Were arranged to stand normally at clear and were not subject to control by approaching trains.

My invention is of particular advantage in the control of trafiic which includes trains operated at relatively high speeds, in which case the control limits for the signals'may be greatly extended in order to provide the stopping distances necessary for the protection of approaching trains if they should happen to pass signals at proceed at exactly the same time.

I shall now describe one for of apparatus embodying my invention and shall then point out the novel features thereof in claims.

- In the accompanying drawings, Figs. 1A and 1B- taken together illustrate the circuits and apparatus for a typical block system of the absolutev permissive type, modified in accordance with my invention and arranged for the control of train movements over a stretch of single track rail- Way which, as shown by the track plan, is equipped with automatic block signals 2 to I5, inclusive. 3 I 1 The main track, as shown, isdivided into sections 2T to I 5T, inclusive, each section being equipped with the usual normally closed track circuit having a track relay'TR at one end energized by a battery ;'I*B connecte d; across the 1 rails at the opposite end.- The signals as shownjareof the color-light typ governed by Polarized relays HD of the retained neutral type controlled over cascade-connected line circuits which include front contacts of the track-relays. The

polarity of the current supplied to each relay I-ID is governed in accordance with the position of the similar relay for the next signal in advance,

or by a pole changer relay PC controlled thereby,

and at intermediate locations,- by directional stick relays SR suchas are generally provided in systems of this character.

A local source of current is provided at each signal location for energizing the various circuits, but to simplify the circuits, only the 'ter--' minals of the sources are shown, these being identified by the reference characters B and C,

which designate the positive or supply terminal and the negative or common returnterminal,

respectively, in each case. Each signal is pro-' vided' with three lamps, as shown in detail for signal 3, including a lamp R which is lighted to indicate stop, when the controlling relay HD is deenergized, and-two lamps Y or G which are lighted to indicate cautionor proceed when the signal relay HD is'energized in its reverse or,

a train is assumed to be nearly equal to the distance from signal I to signal 9 or from signal Ill to signal 8, and to exceed-the distance from signal 5 to signal 1 or from signal l2 to signal I0. It follows that if the signals were arranged to stand I normally at clear, in accordance with the usual practice in automatic block signaling of this type, it would be necessary to extend the control limits for signals 5 and I to the'location of signal l2,

and those for signals l2 and In to the location I of signal 5. This is because of the chance that opposing trains might :pa-ss signals. 5 and ii atclear at the same time, putting "signals 9 and 8- to1stop,'in which case signals land l0 would display caution indications to the approaching trains and the blocks'ections between these two signals would provide the required stopping dis tances.

Assuming that the signals stand normally at clear and that the double track section between signals" H and l2=is a designated meeting point for the approaching trains, the westbound train will pass signal i2 at reduced speed, stopping in section E lT, which is within the extended control limit for signal which it would be necessaryto provide if signals 1 and H} were arranged to stand normally at clear. If at this time the eastbound train is in section 4T, for example, signal it, in front of the standing westbound train would display an unnecessary proceed indication while signals 5, 1 and 9 in front of the eastbound train would each indicate caution, requiring this train to reduce speed upon passing signal 5 and to continue at reduced. speed past signals 3 and 9, even though adequate stoppingdistance would be provided if the train were to proceed at full speed after passing signal 5 and would begin to reduce speed upon passing signal. 9 at caution.

One object of my invention is the provision of means for avoiding the display of unnecessary caution signals such as signals 5 and i in the example described, to a train which is approaching a designated meeting point and thereby overcoming an avoidable delay in train operation.

As shown herein, the circuits for the entering signals '3 and iii are normally open so that these signals stand normally at stop. Signals landiii may be cleared, only one at a time, by the energization of an approach relay JAR or HEAR. by means controllable by the engineman of a train approaching the corresponding distant signal 3 or M, or by the operation of a push button 'FPB or MP3 at the entering signal location. Signals i and I!) are interlocked by time locking relays 'iASR and HBASR governed by thermal relays TI'E' and IBTE, which serve to preventthe clearing of either entering signal for a predetermined time interval following the return of the other entering signal to its stop position. The push buttons PB alsoprovide means enabling the established traffic direction to bereversed, with the permission of the dispatcher, and the relays ASR provide the usual time locking protection effective if signal '1 or I a is manually put to stop in front of an approaching train.

Signal 5 stands normally at caution as shown, and signal 3 as well, in order toprovide adequate stopping distance for a train approaching signal I at stop. Similarly, the two successive signals in the rear of each of the entering signals 4, IB and it stand normally at caution, as shown.

The approach relays EAR and MAR are con trolled by sound responsive devices such as a microphone it located adjacent a wayside marker M a suficient distance in the rear of signal 3- or M, respectively, to enable that signal to assume its proceed aspect before it is passed by an approaching train in response to the actuation of the microphone by a whistle on the train, sounded at the marker location.

Suitable approach control apparatus of this kind is well known, as shown for example, by' Letters Patent of the United States, No. 1,858,897; granted to Samuel M. Lucas, on September 12, 1928, for Railway switch, controlling apparatus; and No. 2,138,878,, granted toRobert M. Phinney, on Decemberfi, 1938, for Railway traificcontrolling system. This apparatus may be variously arranged as pointed, out in these. patents, and as herein shown, the microphone 1:6 in section 2T" is energized by current from a local battery i? in response to the energization of the directional stick relay SSE when an eastbound train enters section ET, and is deenergized by the release of relay 5H8 when the-train enters section 3'1, and

when activated by a whistle signal supplies a tone frequency through suitable amplifying and filter circuits to a rectifier l3 connected to relay EAR, this apparatus being so arranged that relay lAR picks up in response to a whistle signal of suitable character to complete a stick circuit at the lower back contact of relay 'IHD and to close a contact in the circuit for relay 'IHD.

Signal 3 indicates caution for the reason that the signal relay 3I-ID is energized in the reverse direction over a circuit extending over front contacts of the track relays 3TB. and 5TB, and back contacts of relays ZSR and 4HD' associated with the opposing signals, to terminals B and C at the pole changer contacts of relay EPC, which relay is energized only when signal 5 indicates proceed. Signal fi incli'cates caution because relay 5RD is energized in the reverse direction over a circuit extending over front contacts of the track relays 5TB, 5TB, and 'ITR and the pole changer contacts of relay lHD to terminals B and C at the location of signal 1. v

In response to the energization of relay 'IAR, relay 'EHD becomes energized in the normal direction over the circuit including front contacts of relays JAR, 'I'TR, BTR, wires 19 and 20, front contacts of relay SHD, a back contact of relay R, normally closed contacts of push button lllPB and of relay lllTE, to terminals B'- and C at the front contacts of relay IBLASR, causing signal 5 to indicateproceed, and releasing relays TAR and 'lASR.

Relay TASR opens the circuit for relay IDHD, thereby holding signal l6 at stop even thoughrelay HBAR is inadvertently operated by=the blowing of the whistle of a westbound train in section i5T.

Relay EiHD is energized in the reverse direction so that signal 9 indicates caution, over a circuit similar to that for relay 3H1), already traced.

It will be seen therefore that when. relay 'IAR- is actuated by blowing the whistle of an east bound train in section 2'1, with the apparatus in the condition shown, relay ll-ID becomes energized in the normal direction to cause signal I to indicate proceed. Consequently relay 5HD assumes its normal position causing signal 5' to indicate proceed. Relay 511D energizes relay 5P0 whichoperates relay 3I-ID toits normal position causing signal 3 to indicate proceed.

If now the section between signals H and I2" is a designated meeting point for opposing trains, the engineer of the Westbound train will refrain from blowing the whistle at the marker location insection I5T, and will pass signal I2 at reduced speed and stop before passing signal H], which signal will continue to indicate stop. If his train occupies the main track, signal I I will be held at stop and signal 9 at caution. the eastbound train, by blowing his whistle at the marker location in section 2T causes signals 3, 5 and l to indicate-proceed, and his'train is thereby enabled to advance at full speed to signal 9, prepared to stop in the section between signals 9 and.

H, which as already'explained, provides adequate stopping distance.

This results in a considerable. saving in time for both trains, as will be readily apparent in view of the fact that the sections between signals 3 and T and between signals 1 and 9 which the eastbound train would otherwise have to traverse at reduced speed are each ofsufiicient length to provide stopping distance for a high speed train.

It is to beunderstood, that similar arrangements, not shown, maybe provided for the ad'- The engineman of joining blocks having the"enteringsignals I3 and signals 9, l I and [3 to indicate proceed by blowing his whistle in sectionBT to operate an approach relay AR, not shown,'to energize relay I3HD.

It will be seen'that relay 'lHD is arranged as a stick relay, and is released by relay lTRwhen the eastbound train passes signal 1, and when the train enters the track section 8T, relay 96B is picked up by the release of the track relay BTRJ Relay 9H1)" is released when the train enters section QT, andholds relay HSR energized until'the train vacates' section HIT. When relay 95R is energized, relay 'IHD may be energized in the reverse direction by the operation of relay 'IAR by the englneman of a following train, to cause signal I to indicate caution and signals 5 and 3 to indicate proceed. If relay TAR is'operated when the first train is in the section 'IT or 8T, relay 'IHD will remain released, and relay TAR will be held picked up over its stick circuit'so that relay II-ID will pick up when that section is vacated. If the first train is in section 3 T or 4T, or in section 5T or ET, the circuits controlled-by microphone [6 are opened by the release of reIayBI-ID or 5HD, and relay IAR is not controllable by a following train, as

will be obvious. I M

Signal 1 may also be clearedby the operation of the push button 1PB, in the event the microphone in section 2T has not been actuated, as would be the case if the passing tracks between signals 5 and 6 were a designated meeting point and the eastbound train occupied the side track. The push button 'IPB has a normally open contact in the circuit for relay TAR, and a normally closed contact in the circuit forrelay IOI-ID, which circuit is similar to that for relay 'IHD,

Assuming that the double track section between signals II and I2 is the designated meeting point and that signal ll] has been inadvertently cleared by the operation of the'approach relay IIJAR, by the engineman of the Westbound train, although this train stops in the section between signals H and I2. In this case signal I will be held at stop,

due to the fact that signal it has been cleared, and to advance the eastbound train to meet the westbound train in that section, the crew of the eastbound train will operate the push button 'IPB,

thereby energizing relay IAR and releasing relay IIJHD, to return signal ID to stop, whereupon the thermal relay [UTE becomes energized, and after a suitable time interval energizes relay IBASR. Relay I BTE is thereby deener-gized and returns to its normal position after a further time interval, completing the circuit for relay II-ID, which then picks up to release relay IAR and to cause signal from the spiritand scope of my-inventioni- Having thus described my invention, what I? claim is: 1. In combination with a stretch of railway track including a single track section having normally deenergized entering signals at its opposite ends controllable in accordance with traific conditions for governing themovement of traffic into said'section, a distant signal located in the rear of eachentering signal and controlled thereby so as to indicate proceed only when such entering signal is energized, for governing traffic approaching said single track section, an approach relay at each end of thestretch, approach control means manually controllable by blowing a whistle or the like ona train approaching either distant signal for selectively actuating the approach relay, at the corresponding end of said single track section, and means governed by eachapproach relay when actuated for causing one entering signal to be energized in accordance with traffic conditions in said stretch and for preventing the energization'oi the other entering signal. to thereby establish a particular direction for trafiic movements in said section depending upon which approach relay is actuated.

2. In combination with a stretch of railway track including passing-sidingsat its opposite. ends connected by a section of single track, an entering signal at each end of said single track section for governingthe movement of trafficinto such section, a distant signalat each end of the stretch governedyby traffic conditions therein, and reflecting the condition of the associated entering-signal for governing themovement of trafiic approaching such entering signal, an approach relay at-each entering signal location, means controlled by each approachrelay when actuated for causing one entering signal to be cleared in accordance with traffic conditions in the single track sectionandfor preventing the, energization of the :other. entering signal, to thereby select a. particular. direction for trafiic movement into said section, means manually controllable by blowinga whistle or the like on a train approaching either, distant signal, when such signal is energized, forselectively actuating the approach-relay at that end of the single track section.

-3. In combination with a stretch of railway trackincluding asingle track section through which traffic may move in eitherdirection, a blocksignaling systemincluding entering signals for, both directions controllable in accordance withtraffic conditions in said'single track section, a

distant'signal located in the rear of each entering signal, and governed thereby for controlling the movement of traffic toward-such'entering signal in accordancewith traffic conditions in the intervening portion'of said stretch, an approach relay for each direction, located at opposite. endsof said single track'section, control means located in-the trackwayin the rear of each distant Sig-- naland responsive to sound waves from a train whistle or the like, means controlled by each such control means, 'ifoperated when the trackportion between the' adjacentdistant signal and the corresponding end'of the single track section is unoccupied, for selectively operating the approach relay at the corresponding end of the single track sectiongandmeanscontrolled by each approach relay when operated by its control means for closing acircuit' controlling one en-" tering signal" and for opening acircuit 'controlling the other-entering signal to select a particii lar direction for traffic movement in said single track section.

4. In combination with a stretch of railwa 1 track including an approach section at each end and an intervening single track section through which traiiic may move in either direction, an entering signal at each end of said single track section, a signal relay for each signal having an energizing circuit controllable in accordance with trafiic conditions in said single track section, an

approach relay for each entering signal, control means located in the trackway in approach to each entering signal effective when actuated to pick up the approach relay for such signal, a stick circuit for each approach relay which is opened when the signal relay for the associated entering signal is energized, means controlled by each approach relay when energized for closing the energizing circuit controlling one entering signal and for opening a circuit controlling the other entering signal to select a direction for traffic movements in said single track section which depends upon which signal relay is energized, and manually operable means on a train effective only when such train is approaching but has not entered said stretch for selectively actuating the control means for the approach relay for the entering signal which such train is approaching to pick up such approach relay.

5. In combination with a stretch of railway track including an approach section at each end and an intervening single track section through which traflic may move in either direction, an entering signal at each end of said single track section, a signal relay for each signal for governing the indications displayed by such signal, an en ergizing circuit for each signal relay controllable in accordance with trafiic conditions in said single track section, an approach relay for each entering signal having pick-up and stick circuits, control means located in the trackway in approach to each entering signal eiTective when actuated to pick up the approach relay for such signal to complete its stick circuit, means con trolled by each approach relay when energized for controlling the energizing circuits for said signal relays to govern the indications displayed by both signals to designate a direction for traffic movements in said single track section which depends upon which approach relay is energized, manually operable means on a train effective only when said train is approaching but has not entered said stretch for selectively actuating the control means for the approach relay for the signal which said train is approaching to pick up such approach relay, and means for releasing the energized approach relay controlled by the associated signal relay and rendered efifective when such signal relay becomes energized.

6. In combination with a stretch of railway track including an approach section at each end and an intervening single track section through which trafic may move in either direction, an en-' tering signal at each end'of said single track section, train carried acknowledging means by which the engineman of an approaching train may indicate whether or not it is his intention to stop in the adjacent approach section without entering said single track section, a signal relay for each signal for governing the indications displayed thereby, an energizing circuit for each signal relay controllable in accordance with trafiic.

conditions in said single track section, an approach relay at each end of said single track secion, control means in the trackway at locations adjoining the ends of the stretch for actuating the approach relay at the corresponding end of the single track section in response to the operation of the acknowledging means on an approach ing train, and means controlled by each approach relay when actuated for so controlling the energizing circuits for said signal relays that one entering signal is held at stop while the other is caused to display a less restrictive indication for the control of traffio movements into said single track section in a direction dependent upon which approach relay is energized.

'2. In combination with a stretch of railway track including an approach section at each end and an intervening single track section through which trafiic may move in either direction, an entering signal at each end of said single track section and a distant signal in the rear thereof for governing traific movements into the adjacent approach section, train carried acknowledging means by which the engineman of an approaching train may indicate whether or not it is his intention to stop in the adjacent approach section without entering said single track section, a signal relay for each signal for governing the indications displayed thereby, an energizing circuit for each signal relay controllable in accordance with trafiic conditions in said stretch in advance of the signal which such relay controls; an approach relay at each end of said single track section, control means in the trackway in the rear of each distant signal for energizing the approach relay at the corresponding end of the single track section in response to the operation of the acknowledging means on a train approaching such distant signal, and means controlled by each approach relay when energized for so controlling the energizing circuits for said signal relays that one entering signal is held at stop to hold a train at a designated meeting point which includes the approach section at one end of the stretch and the other entering signal and its distant signal are caused to display less restrictive indications to advance a train governed thereby with less delay to said meeting point.

8. In combination with a stretch of railway track including an approach section at each end and an intervening single track section having an entering block signal at each end, approach con- 1 trol means at the opposite ends of said single track section, circuits for clearing said block signals to establish opposite directions for traffic movements through said single track section in accordance with trafiic conditions therein, train carried acknowledging means including a call signal transmitter operable by the engineman of a train approaching said stretch, a wayside receiver for each end of the stretch responsive to the operation of the transmitter on a passing train for actuating the approach control means at the corresponding end of said single track section, means governed by each approach control means when actuated for holding the block signals for one direction only at stop to thereby establish the opposite direction for trailic movements through said single track section and means associated with said signals for maintaining such direction established only until a train passing through said stretch in said opposite direction vacates said single track section.

' 9. In combination with a stretch of railway track including an approach section at each end and an intervening single track section having an entering block signal at each end, circuits fortrafi'ic conditions in said single track section, approach control means at each end of said section for governing said signal circuits, each effective when actuated to prevent the clearing of the block signal at one end only, and thereby establish opposite directions for trafiic movements through said single track section, train carried acknowledging means including a call signal transmitter, and a wayside receiver responsive to the operation of said transmitter by the engineman of a train when approaching said stretch for actuating the approach control means at the adjacent end to establish a particular direction for traflic movement through said single track section, and means rendered effective when a train enters said single track section for maintaining such directional control only until the single track section is vacated.

10. In combination with a stretch of railway track including an approach section at each end H and an intervening single track section having an entering block signal at each end, circuits for controlling said block signals in accordance with traific conditions in said section, approach control means at each end of said section, each effective when actuated to open a circuit controlling one entering block signal and to close a circuit for clearing the other entering block signal, train carried acknowledging means including a call signal transmitter operable by the engineman of a train when approaching said stretch, and a wayside receiver responsive to the operation of the transmitter on a passing train for actuating said approach control means.

11. In combination with a stretch of railway track including an approach section at each end and an intervening single track section having entering block signals at its opposite ends, signal circuits for controlling said block signals in accordance with traffic conditions in said single tracksection, a distant signal located in the rear of each entering block signal for governing trafiic approaching said single track section, approach control means at the opposite ends of said single track section each effective when actuated to control said signal circuits, one approach control means being effective to establish one direction and the other the opposite direction for trafiic movements through said single track section, train carried acknowledging means including a call signal transmitter operable by the en- 'ginei'nan of a train approaching said stretch, a

REFERENCES CITED The following references are of record in the file of patent:

UNITED STATES PATENTS Number Name Date 1,144,509 Taylor June 29, 1915 1,194,116 Abernathy Aug. 8, 1916 1,294,736 Wight Feb. 18, 1919 1,858,897 Lucas May 17, 1932 2,030,924 Kemmerer Feb. 18, 1936 

